Gauge



23, 1940. lla. s. Bar-:scm Erm.

ewes' Filed ual-m1011938 FIG. l.

FIG. 2.

/NvE/vroks y n. s. eng-scm E. ./.y Hume@ ATTORNEY Y Patented Apr. 1940 um'rlznl STATE-s GAUGE Rudolph S. Brescka, Cranford, and Edward J. Meagher, Westfield, N. J assgnors to Western Electric Company.- Incorporated, New York,

A N. Y.. a corporation of New York Application March 10, 1938, Serial No. 195,004

12 Claims.

This invention relates to a gauge and more particularly to a plug gauge for testing electrical apparatus. In the manufacture of sviritchboards,v particularly those in the art of telephony, it is necessary to provide each switchboard with a multipli'city of switches, each of which includes a spring jack which may be moved to complete a circuit or circuits through the aid of la plug.

In order to determine whether or not the springs of the jacks are positioned accurately they are tested by means ofa gauge patternedafter the switch plugs which will be used therewith commercially The eifective and accurate life of gauges of this type has been relatively short because the commercially known conductive and insulating materials which might be used in forming such a gauge lack suilicient durability and resistance to abrasion'to withstand the wear va.) jacks with conductive rings for electrically contactingthe springs of the jacks and insulating sleeves formed of hard surfaced materials disposed on-each side of the conductive rings.

Other objects of the invention will be apparent .u from' the following detailed description when i taken in conjunction with drawing, wherein Fig. l is a side elevational view of a gauge embodying the invention, shown associated with 40 a spring jack, and

the accompanying Fig. 2 is an enlarged sectional fragmentary view-of the gauge, with portions thereof shown in elevation. l Referring, now to the drawing, numeral Il designates a shank axially apertured at Il to v receive one end oi a pin I2, the opposite end of the pin having integral therewith a tip I3, larger in diameter than the pin. to form a shoulder I4. Adjacent one end of-theshank Il is an enlarged 50 portion i3 forming an abutting shoulder Il for a purpose hereinafter described.. A threaded projection 2i integral .with the portion Il andA extending axially therefrom receives a diskshaped 'guard 22 and a handle 23. The portion of the shank il adjacenttheendwhichisoppo- (Cl. 179-1751) f site the'enlarged portion I3 is bevelled as at 26 away from the end surface 26.

Positioned between the shoulder' I4 of the tip and the surface 26 of the shank, and mounted. upon the pin l2,fare conductor rings 36 and 3l 5; separatedfrom each other by an insulating sleeveA 32 and from the shoulder I4 and the surface 26 by insulating sleeves or rings 33 and 34. This assemblage of the rings 36 and 3i and the sleeves 32, 33 and 34 brings about an interrupted con- 10 ductive surface but the rings are electrically associated with the shank I0 through the pin Il. In the present embodiment, the sleeve 33, the ring 30, and the adjacent portion 36 of the sleeve 32 have diameters equal to the diameter of the 15 surface I4 on the tip I3. The portion 36 of the sleeve 32 has its periphery :joined to the periphery of the remaining portion, 31 of the sleeve through a bevelled, portion 35 vhaving an angle of approinmately 45. The diameter of portion 20 31 of the sleeve 32,`the diameter of the ring 3l, and the diameter of the sleeve-34 are all equal, but greater than the diameter of the surface 26. Jack springs of' the type as indicated at 40 and 4| (Fig. 1) have their ends formed substantially 25 V-shaped, the apices thereof forming the contact points or edges. Gauge plugs ofv this type are used to determine whether or not the contact points of the springs are positioned properly relative to each other and relative to the outer surface 42 of a panel 43 containing a metallic sleeve 44 which is included with the springs in the electrical circuits. The spring 4I serves to actuate a make contact 48 when moved a desired distance, this movement being caused 85 by the portion of the gauge. The springs and 4I must have sufficient resiliency and durability to assure long life thereof, but such resiliency and durability of the springs are apt to cause wear on a gauge plug which is o used repeatedly for making such tests. When the commercially known types of insulating material have been used for the sleeves in a gauge of thistype to separate -the conductive rings vfrom each other-andfrom the tip and the shank,

variations in the materials caused by changes in temperature or humidity and from other causes affect the gauge so thatv its efficient life is Irelatively short.

For the purpose of illustration, fibre and rubber, when used as insulators, are aiected vby humidity changes and'niay eitherdecrease or' increase in diameter `due to such changes, such variations render the gauge ineffective to give accurate readings during a' test for the followv ing reasons: First, if the insulating sleeve should decrease in diameter the portions of the contact springs in )advance of the contact points would contact with the respective rings whereas only the contact points should engage the rings; second, if the insulating sleeve should swell they would delay the engagement of the contact points with the rings; and third, if the sleeve should decrease in diameter the sharp edges of the rings would scrape oi! particles of metal from the springs which would adhere to the outer surfaces of the sleeves adjacent the conductive rings to Widen their spring engaging areas and thus further rendering the gauge plug inemcient for the purpose intended.

When other insulating materials, such as Bakelite, bone, ivory and also various plastics are used for these sleeves it has been the tendency of such materials, when subjected to the scraping action of the springs, to' wear in such a manner than some of the materials is scrapedV off by the springs and deposited upon the outer surfaces of the conductive rings, rendering them ineffective tok accurately lgauge the switches. Furthermore, when such materials wear away, inaccurate readings may result from the variations in diameters of the insulating material.

To overcome these disadvantages and to produce a gauge which will not only resist wear but will be substantially unaffected by changes in temperature, humidity, etc. and will thus remain accurate and dependable almost indenitely, a conductive material for the rings 30 and 3l and an insulating material for the sleeves 32, 33 and 34 have been selected which are sub: stantiallyequalin degree of hardness. For example, the sleeves 32, 33 and 3i may be formed from one of the following insulating materials, which are considerably harder than the aforementioned commercially known insulating materials and may be termed hard surfaced material, the degrees of approximate hardness measured by Mohs scale ofA hardness being given for each material:

Corundum 9 Sapphire 9 Ruby Y, 9 Diamond l0 Bort -10 'Ihe conductor rings are formed of hard metal bodies and may be called hard metal electrical conductor elements. The term hard metal bodies relates-to materials such as metal carbides. The term metal carbides refers to the.

material commercially known as such and alf' though its contents are not publicly. known 'it is presumed to be formed of desirable metals or alloys such as tungsten, tantalum, vanadium orv stellite, and may or may not include lower melting materialssuch as chromium, molybdenum,

and to further aid in rendering them. such theyl may be chromium plated.

Hard surfaced materials such as carbides an the aforementioned insulating materials are relatively brittle and in order to assure accurate assembling of the sleeves and rings -upon the pin might cause the materials to be fractured in assembly. The cushioning material eliminates any possible fracture of the material in the rings or sleeves when suiicient pressure is applied t0 force the various parts in assembled relation. A

The gauge is constructed so that the dimen- `sion between the shoulder I9 and the nearest edges of the rings 30 and 3l will be within predetermined limits less than those required for the commercial plug. The same is true of the dimensions of the width of the conductor rings and the distance between these rings. Consequently, if the circuit or circuits including the springs 40 and 4I and the sleeve I4 are closed when the gauge plug is inserted in place, it will be assured that the relative positions of' the springs and the sleeve will be proper for the commercial type plug.

'Ihe disk-shaped guard 22, which may `be formed of any suitable material such as fibre, serves to space the gauging end of the plug from contact with objects when not in The handle 23 is of suiiicient size and weigh to cause the entire unit to rest upon the disk and the outer portion of the handle when laid upon a support,

` thus protecting Vthe outer end of the gauge plug.

The connection between the pin l2 and the apertured shank is shown as a press iit but these members may be provided with threaded connections, or secured by a suitable pin or in any other desired manner.; Furthermore, the rings 3B and 3l and the sleeves 32; 33 and 34 may be formed/with other than round cross sections if f it is so desired.

Although the invention is herein disclosed as applied to use in connection with spring jacks, it is obviously not so limited but is applicable tov other fields where electrical and physical tests are made. The invention'is limited only by the spirit and scope of the appended claims.

What is claimed is: l

1. In a gauge for testing electrical apparatus, adjoining friction bearing surfaces of conducting and insulating materials having similar and high degree ofv hardness.

2. In a gauge for testing electrical apparatus,

-adjoining friction bearing surfaces of conducting and 4insulating materials having similar and high degree of hardness, the insulating material being sapphire.

3. In a gauge for testing electrical apparatus,- adjoining friction bearing surfaces of conducting and insulating materials having similar andV high degree of hardness, the insulating material being ruby.

4.v In a gauge for testing electrical apparatus, adjoining friction bearing surfaces of conducting and insulating materials having similar and high degree of hardness, the insulating material being diamond. l

5. In a gauge for testing electrical apparatus, adjoining friction bearing surfaces of conducting and insulating materials having similar and high degree of hardness, the conducting material being hard metal.

6.7In a gauge for testingelectrical apparatus, adjoining friction bearing surfaces of conducting and insulating materials having similar and high degree of hardness, the insulating material 9. In a gauge foi testing electrical apparatus, l

adjoining friction bearing surfaces of conduct.- ing and insulating materials having similar and high degree of hardness, the conducting material being selected from the group consisting of tungsten carbide, tantalum carbide, vanadium carbide and stellite' carbide.

10. In a gauge for testing electrical apparatus,

a shank, an annular conductive gauging member disposed on the shank, and an annular insulating member disposed on the shank adjacent the conductive gauging member, the surfaces of the members having similar and high degree of hardness.

l1. In a gauge for testing electrical apparatus, adjoining friction bearing surfaces of insulating and conducting materials both having -surface .hardness of approximately nine as measured by Mohs scale of hardness.

12. In a gauge for testing electrical apparatus, a conductive material having a hard friction bearing surface, and an adjacent insulating material having a friction bearing surface of equal hardness.

EDWARD J. MEAGHER.

RUDOLPH VAs. BRESCKA i0 

